<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <p>ww
    <!-- // 可以向文档写入html表达式 -->
    <script>
        document.write("hellow World");
        document.write("<p>Document title: " + document.title)
    </script>
    
</body>
</html>